The content of ferromagnetic fraction or phase in many cases is to be determined to give the answer to the problem of advisability of using in a certain technology magnetic separators of the kinds widely utilized in various industries, and also to assess the expected efficiency of their performance. In such cases, the availability of veritable information on the quantity and percentage of the ferromagnetic fraction of the solid inclusions enables to give in advance an adequately accurate answer on whether the separator is going to operate efficiently, and whether its incorporation is feasible or not. By having made trustworthy measurements of the quantity and percentage of ferromagnetic solid phase at various points and in various streams of the production process flow, it is also possible to draft an optimized, efficient and economic design of installing the magnetic separator at minimum cost and with time saved.
There are known various methods of determining the quantity of the solid fraction or phase of ferromagnetic matter in a fluid, based on the principle of magnetic separation of solid particles carried by the fluid. Thus, in an article titled "Determining Magnetic Forms of Iron Compounds in Water of Electric Power Stations" by A. V. Sandulyak et al. published in Vol. 9 of the "Izvestia Vuzov SSSR-Energetika" scientific and technical magazine, 1979, there is described an approximation method including taking a sample of a predetermined volume of a fluid to be analyzed, carrying iron-containing impurities, ferromagnetic ones included, recirculating it through magnetized ferromagnetic packing and measuring the content in the fluid, after its passage through the packing and before its re-entry (and also prior to the recirculation), of every iron-containing impurity, e.g. by the sulphosalicylate or ortophenanthronile technique, the recirculation being continued until unvariable or permanent content of the iron-containing impurities is attained. Then the content of the ferromagnetic matter is found by subtraction of the found quantity of the residual content of iron-containing impurities from the initial content of these impurities.
A shortcoming of this method is the fact that, although offering a higher accuracy then another known "magnetic" method (e.g. by separation over a permanent magnet, or else separation in a wedge-shaped magnetic gap), the method is not proof against errors developing when the optimized flow velocity duty is not strictly observed, and also when there are not ensured conditions precluding unwanted, in this case, aggregation (or flocculation) of the particles that have passed through the zone of magnetic action. What concerns the abovementioned flow velocity duty, the probable error of the known method may be caused by the fact that with relatively low filtration velocities, non-ferromagnetic particles tend to settle alongside of ferromagnetic ones, thus stepping up the obtained value of the ferromagnetic fraction of the particles. And vice versa, with relatively high filtration velocities some turbulence develops in the pores of the packing, affecting the magnetic settling of ferromagnetic particles and, besides, resulting in some particles that have already settled being carried away, whereby the obtained value becomes unduly low.